Synthesis of Ionizable Calix[4]arenes for Chelation of Selected Divalent Cations |
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| Authors: | Markus Blumberg Karrar Al-Ameed Erik Eiselt Sandra Luber Constantin Mamat |
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| Institution: | 1.Helmholtz-Zentrum Dresden-Rossendorf, Institut für Radiopharmazeutische Krebsforschung, Bautzner Landstraße 400, D-01328 Dresden, Germany; (M.B.); (E.E.);2.Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, D-01062 Dresden, Germany;3.Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland; (K.A.-A.); (S.L.) |
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| Abstract: | Two sets of functionalised calix4]arenes, either with a 1,3-crown ether bridge or with an open-chain oligo ether moiety in 1,3-position were prepared and further equipped with additional deprotonisable sulfonamide groups to establish chelating systems for selected cations Sr2+, Ba2+, and Pb2+ ions. To improve the complexation behaviour towards these cations, calix4]arenes with oligo ether groups and modified crowns of different sizes were synthesized. Association constants were determined by UV/Vis titration in acetonitrile using the respective perchlorate salts and logK values between 3.2 and 8.0 were obtained. These findings were supported by the calculation of the binding energies exemplarily for selected complexes with Ba2+. |
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| Keywords: | calixarenes barium chelation |
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